Joseph van ackeren



I. VAN ACKEREN.

AMMoNm AND TAR RECOVERY PHocEss.

APPLICATION FILED lMAY 26| I9I9. I1,826,369 Patented Nov. 4, 1919.

I l -V I I l l I l I Y l l I l l l l l I I I l v I I I l l n man.

Original application led August 12, 1918, Serial No. 249,381. Divided and this 1 191B. Serial No. 299,854..

UNITED sTATEs PATENT oEEicE.

` JOSEPH VAN ACKEBEN, OF PITTSBURGH, PENNSYVLVANIA, ASSIGNOR '.lO THE KOPPERS COMPANY, 0F PITTSBURGH, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA.

AMMONIA AND TAR RECOVERY PROCESS.

esses, of which the following is a specification.

My invention relates primarily to the recovery of tar and of ammonia from producer-gas and from coke-oven gas and has for an object the efficient productio'n of a clean, dust-free and high-grade tar, and for a further object the recovery of ammonia from the gas, and the production of hi hgrade ammonium sulfate; and-the invention may also be applicable to the treatment of a gas or gases lotherwise derived from the carbonization of coal, and may also have such other objects and results as are found to obtain in the processes herein set forth and claimed. This application is a division of my copending application Serial No. 249,381 filed August 12, 1918 and allowed May 2l, 1919, and certain of the matters disclosed in the herein followin specification, but not herein claimed, are c aimed in said original copending application.

In the' accompanying drawings. Figure 1 is a conventional diagram illustrating an embodiment of the invention in a preferred arrangement of apparatus for practising its processes; and Fig. 2 is a key to the symbols employed in the various lines that show the connections between the apparatus indicatedin Fig. 1.

5 indicates aY cokeoven battery from which coke-oven gas is derived and that is fired with producer-gas derived from the as-producer 6. The evolved producer-gas rom said gas-producer 6 passes rst to the electrical preclpitator 7. Such producergas enterin the electrical precipitator is still at Very igh temperature, about 450 C., and its water saturation point is only about 80 C., and therefore it is still greatly superheated in respect of its water and tar and these, and its other vaporizable content, are carried as vapor into and through ,such precipitator 7 and said precipitator acts only Specification of Letters Patent.

to .free the passing gas from dust and other solid impurities in its current. From said preclpltator 7 the producer-gas., without havlng undergone appreciable cooling, passes to the superheater 8, through which it iioWs in countercurrent with the saturated air that is on the way to the producer. This saturated air has a temperature of about 70 C. when it enters the said superheater 8; and as a result of the heat interchange in passing through this superheater, the producer-gas issues with its temperature reduced to about 280 C., and the air issues with its temperature raised to about 220 C. and at such temperature passes to the grate of the producer 6. The partially cooled producer-gas from the said superheater 8 passes, still carrying its water and tar as vapor, to the Water-sprayed cooler 9, which has the primary function of further cooling thc gas.

vto a large extent, and the incidental function of further cleaning such gas by precipitating any residue of dust or other solid impurities. A slight amount of tar may also be taken out in said cooler 9 and required to be drained from its discharge trough 10 into the tar tank 11, the Waste-Water from said trough 10 discharging through the outlet line 12. But nearly all of the tar is carried though said cooler as vapor in the gas because the gas enters the cooler at a temperature of about 280 C. and is still superheated when leaving it, though cooled down toward about 90 C. Such still superheated producer-gas passes from said cooler 9 to the compartment 13 of an electrical precipitator, which it enters at a temperature ofabout 90 C., and at such temperature the tar, approachin the character of a nely comminuted mist, will be precipitated; and the pclean tar so precipitated is discharged into the tar and liquor tank 14, from which it Hows into the aforesaid tar-tank 11. The producer-gas passes from said' tar-precipitatorcompartment 13 through the gas-line -15 to the hot acid-washer tower 16, which it temperature of about 82 C., still slightlyV above its saturation point of 80 C., the

acid-solution being kept hot by the absorpvand water flows to the sewer.

tion reaction, so'that there can not be any diluting of the ammonia absorbing acid-solution that is flowing through said acid washer; and by reason of the little superheat -remaining in the gas practically no water is picked up by the gas in passing through said acid washer, and so there is no precipitation of ammonium sulfate in said acid washer. Thence the ammonia-freed gas Hows through the acid separator 17, in which it is freed of such acid as it may carry with it, and then flows through the gas-line 18 to the first-stage final-cooler 19, through which it flows in counter-current with warm water that enters such cooler at about 50 C. In this cooler the gas is cooled to about 65 C. and to a great extent dehydrated and thence passes, through the gas-line 20, to the second-stage final-cooler 21, through which` it passes in counter-current with cold water and issues finally dehydrated and cooled to a temperature of about 25 C. Such clean, cool:l and relatively dry producer gas is drawn olf', through the gas-line 22, bythe exhauster 23, and thence is forwarded to the producer-gas holder 24 and on, through the producer-gas line 25, to the before-mentioned coke-ovens 5, in which such producergas is burnedto provide the heat for the coking of the coal-charges of the ovens.

The ammonia-charged acid-solution from the aforesaid acid washer 16 is conveyed to the mother-liquor tank 26, which feeds the saturator 27. Said mother-liquor tank 26 also receives the drain from the saturators drain-table 28 and centrifugal drier 29; and the surplus acid-solution 'from said motherliquor tank is forced back, by the acid-pump 30, to the acid-washer 16, maintaining a constant circulation of the hot acid-solution, to which a proportion offresh acid is constantly added from the acid-tank 3-1.

rlhe before-mentioned prima cooler 9 and second-stage final-cooler 21,1fbr the producer-gas, are cooled by fresh water continuousl supplied from the water-tank 32,

rom both of these coolers the waste- But the firststage final-cooler 19, for the producer-gas, receives its warm water, at a temperature,

as before mentioned, of about 50 C., from the air-saturator tower33, from which.s'uch v water is drawn by the warm-water pump 34; and the water issuing --from said first- Nffasification conditions in the gas-prolducer 6.

The coke-oven gas from the coke-ovens passes through the gas-line 39, at a temperature of about 80 C., to the primary cooler 40 and thence is forwarded, by the exhauster 41, to the compartment 42 of the electrical precipitator whose other before-mentioned compartment, 13, serves for the precipitation of tar 'from the producer-gas. I n the primary cooler 40 the coke-oven gas is cooled to about 25 C. and the consequent condensate of tar and ammonia-liquor is drained from such cooler and conveyed to the tar and liquor tank 14, in which the tar and ammonia-liquor are separated, the tar flowing olf into the tar tank 11 and the ammonia-liquor liowing to the ammonia-still i compartment stage final-cooler 19 has atemperature of about 80 C. and is-forced, by the hot-water i pump 35, to the top of the said air-saturator tower, into which it is sprayed,-there being, as just mentioned, a constant recirculation of water through said first-stage finalcooler and said air-saturator. The air to be saturated and heated isforced into said air-saturator tower by the air fan 36, and enters the. tower at a temperature of about 43. The vapors from this temperature of about 100 ammonia-vapor line 44 leading into the coke-oven gas-line and the electrical precipitator compartment 42, and the mixture of such vapors and coke-oven gas enters the said precipitator at a temperature of about 354 C. At this temperature both the tar residue in the cokeoven gas and the water of the still-vapors will be precipitated, in said precipitator 42, and the so precipitated tar and condensate flow oli' from the precipita,- toi into the before-mentioned tar and liquor tank 14. rlhe tar-freed coke-oven gas, with its own content of ammonia and its admixture of ammonia-vapor from the still, Hows from the electrical precipitator compartment 42 to the before-mentioned saturator 27, entering the same at a temperature of about 35 -C. Or such temperature may be.

raised a little by passing the glas through the small reheater 45, around w ich the gas is preferably by-passed on its way from e said precipitator 42 to the said saturator J27. Discharging through the saturation-bath of the said saturator 27, the coke-oven gas both gives up its ammonia and effects the evaporation requisite to precipitate the amstill flow, at a' C., through the between the exhauster 41 monium sulfate derived not only from said ammonia of the coke-oven gas but also from the ammonia ofthe acid-solution from the acid-washer` 16 for the producer-ga s, tl1us accomplishing a combined and simultato Whatever service it may be employed in.'

The processes of the invention may be practised in various Ways, other than the particular embodiment that has been described for purposes of illustration, and

still bc Witliiii tlie scope and subject matter of the claims hereinafter made.

I claim:

1. In a process for the recovery oftar from prodiiccrfgas, the combination of steps that consists i-n: electrically precipitating the dust from said gas While still superheated in respect of its tar vapor and water vapor content; partially cooling saidl dust-freed gas to bring its tar content into the condition of a inely comminuted mist;

. and electrically precipitating the tar While the gas is still. superheated in respect of its Water content; substantially as speci'ied.

2. In a process for the recovery of tar from ammonia-charged gas, thecombination of steps that consists in: electricaly precipitating the dust from said gas while still siiperheated in respect to its tar vapor and Water vapor content; partially cooling said dust-freed gas to bring its tar content into the condition of a finely comminuted f mist; electrically precipitating the tar while the gas is still superheatedinrespect to its Water content; and then effecting ref covery of the ammonia from. the gas; subi stantially as specied. l

3. In a process for the recover of condensates from gas laden with solid matter and with condensable hydrocarbons, the

combination of steps that consists i-n: electrically precipitating the solid matter from said gas While superheated in respectto its condensable hydrocarbons; partially cooling said gasto initiate the condensation of said condensates; and electrically precipitating such condensates; substantially asspec 4. Ina process for the recovery of tar from producer-gas, the combination of steps that consists in: electrically recipitating the ,dust from .said gas While still superlieated in respect of its tar vapor and Water vapor content; partially coollng said dust-freed gas to bring its tar content into the condition of a finely comminuted mist; and electrically precipitating the tar; substantially as specified.

5. In a process for the recovery of tar y from ammonia-charged gas,the combination of steps that consists in: electrically precipitating the dust from said gas while still -superheated in respect to its tar vapor and Water vapor content; partially cooling said dust-freed gas to brlng its tar content into the condition of a finely comminuted mist; electrically precipitating the tar; and then `effecting recovery of the ammonia `rom the gas; substantially as specified.'

In testimony whereof I have hereunto 'set my hand 1n the presence of two subscribing witnesses.

, JosErH VAN ACKEREN.

Witnesses;y

HENRY LOVEv CLARKE, ETHEL Woon. 

